This invention relates to impact printers of the type employing rotatable print wheels and, more particularly, to apparatus for loading a print wheel contained in a cartridge onto the shaft of the print wheel drive motor.
U.S. application No. 767,249 now U.S. Pat. No. 4,124,312 filed on Feb. 10, 1977 in the name of Robert A. Johnson and assigned to the assignee of the present invention, and U.S. application No. 767,250 now U.S. Pat. No. 4,127,335 filed on Feb. 10, 1977 in the names of David L. Bogert and Jammie D. New and also assigned to the assignee of the present invention, disclose a number of devices for loading a print wheel contained in a cartridge onto the shaft of the print wheel drive motor. As pointed out in such applications, the use of print wheel cartridges and associated loading mechanisms enables easy print wheel removal and exchange without having to first pivot the entire print wheel-drive motor assembly to expose the front face of the wheel, as is currently done in commercial daisy-wheel printers.
The print wheel loading apparatus disclosed in the aforementioned U.S. Pat. No. 4,127,335 requires relative motion between the print wheel cartridge and the guide member therefor in two directions, i.e., the cartridge is first moved along the guide member in a direction generally transverse to the axis of the motor shaft, and is then pivoted relative to the guide member in a direction towards such shaft to thereby load the print wheel onto a drive coupling member affixed to an end of the shaft. Having two relative movements required between the print wheel cartridge and its guide member increases the possibility of misregistration of the print wheel hub and the drive coupling member on the motor shaft.
It would be desirable, therefore, to provide a print wheel loading apparatus of the general type disclosed in the aforementioned U.S. Pat. No. 4,127,335, but wherein the relative motion required between the print wheel cartridge and the guide member to load the print wheel onto the drive coupling member is reduced to motion in only a single direction.